1. Field of the Invention
In general, this invention pertains to devices that assist physically impaired individuals. Specifically, this invention pertains to devices that assist individuals in going from a sitting position to a standing position and also from a standing position to a sitting position.
2. Background Information
There are basically two types of devices already available for helping a physically impaired individual go from a sitting position to a standing position and vice versa. The first type is a complete chair that has a mechanized seat for helping a person up or down. The second type is a spring-assisted portable seat that can simply be placed on the seat of another chair.
The first type, while being totally sufficient with respect to sitting and standing assistance, has the disadvantage of not being readily portable for the individual who requires help with sitting and standing in many places.
Typical construction of the second type of device consists of a seat that is hinged to a base along the front edge of the device. When this device is in the down (sitting) position, a spring is compressed between the base and the seat. To raise the seat to a standing position, the spring is allowed to push the seat away from the base in a book-like manner. A latch is usually provided to lock the seat in the down position. This second type, while being portable, has several drawbacks. First, the spring has to be carefully matched to the user's body weight so that the person is able to fully compress the spring by sitting on the device. Because of the nature of a spring, this device can never provide all of the force necessary within the operating range of the device to take a person to a sitting position or return them to a standing position. Second, this device fails to provide the proper range of motion that is needed to comfortably sit or stand. This is due to book-like hinge design which does not provide any lifting capability to the front of the seat connected to the hinge. A third disadvantage is that this device does not give any flexibility to the user between the open (standing) position and the closed (sitting) position. For example, once the user starts to stand, they must complete the move or return to a sitting position. Finally, once the user is standing, there is no convenient way to close the device in order to transport it short of having someone sit on the device again to close it.